The iconic Star Trek captain recently teased on Twitter his gig on the Syfy series. Now, TVLine can exclusively reveal that Shatner will recur in a four-episode Season 5 arc in “a seminal role,” as a pivotal character that has the potential to forever impact the fate of the town of Haven and its Troubled residents.

Syfy’s Haven airs Fridays at 7/6c. In tonight’s episode, Duke’s rolling Troubles and a new threat to Audrey force them each to seek the help of potentially dangerous allies. On Nov. 28, divided loyalties put Haven’s heroes at odds with one another. Then in the Dec. 5 midseason finale, Mara’s endgame is finally revealed, forcing Audrey and Nathan to enact a plan to stop her once and for all.